Stabilized distillate fuel oil



States 3,031,282 STABILIZED DISTILLATE FUEL OIL Harry J. Andress, Jr., Pittman, and Paul Y. C. Gee, Woodbnry, N.J., assignors to Socony Mobil Oil Company, Inc., a corporation of New York No Drawing. Filed Jan. 7, 1958, Ser. No. 707,472 6 Claims. (Cl. 44-7 1) This invention relates to the improvement of non-lubricating petroleum fractions. It is more particularly concerned with distillate fuel oils containing additives adapted to inhibit the appearance of sediment during prolonged storage periods, to prevent screen-clogging, and to prevent rusting of ferrous metal surfaces;

It is well known that fuel oils are prone to form sludge or sediment during periods of prolonged storage. This sediment, of course, has an adverse effect on burner operation, because it has a tendency to clog screens and nozzles. In addition to sediment formed during storage, most fuel oils contain other impurities, such as rust, dirt, and entrained water. The sediment and impurities tend to settle out on equipment parts, such as nozzle, screens, filters, etc., thereby clogging them and causing the equipment to fail A further factor, incident to the storage and handling of fuel oils, is the breathing of storage vessels. This results in the accumulation of considerable amounts of water in the tanks, which presents a problem of rusting in the tanks. Then, when the oil is removed for transportation, sufficient water may be carried along to cause rusting of ferrous metal surfaces in pipelines, tankers and the like.

Generally, it has been the practice to overcome the aforedescribed difficulties with a separate additive for each purpose, i.e., with a sediment inhibitor, an anti-screen clogging agent, and an antirust agent. The use of several additives, however, gives rise to problems of additive compatability, thus restricting the choice of additive combinations. In addition, of course, the use of a plurality of additives unduly increases the cost of the fuel. It has been proposed to overcome two difiiculties, e.g., sedimentation and screen clogging, with one additive. Insofar as is known, however, no single addition agent has been found efiective against sedimentation, screen and nozzle clogging, and rusting of ferrous metal surfaces. j It has now been found that all three problems, i.e., sedimentation, screen clogging, and rusting, can be solved by the use of a single fuel oil addition agent. It has been discovered that a distillate fuel oil containing minor amounts of certain amic acids and amine salts thereof is effectively inhibited, simultaneously, against all three aforementioned difiiculties.

Accordingly, it is a broad object of this invention to provide a fuel oil having properties improved with a minimum number of addition agents. Another object is to provide a fuel oil having a single additive adapted to inhibit sedimentation, to prevent screen clogging, and to prevent rusting of ferrous metal surfaces with which it comes in contact. A specific object is to provide a fuel oil that contains certain amic acids or amine salts thereof that achieve these results. Other objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description.

The present invention provides a distillate fuel oil containing a minor amount, suflicient to inhibit sedimentation and screen clogging and to prevent rusting of ferrous metal surfaces in contact therewith, of a compound selected from the group consisting of '(1) a succinamic acid having the formula:

3,31,282 Patented Apr. 24, 1962 C COOH and 0 COOH RHN 0 BEN wherein R is an aliphatic hydrocarbon radical of an aliphatic primary amine having between about 4 and about 30 carbon atoms per radical, and the amine salt of these amic acids with an aliphatic primary amine having between about 4 and about 30 carbon atoms per molecule. The amic acids contemplated herein can be made by any method for preparing such compounds that is known to the art. They are produced, preferably, by Warming succinic acid anhydride or maleic acid anhydride, respectively, with an aliphatic primary amine having between about 4 and about 30 carbon atoms per molecule to form the monoamide of the acid. This can be done readily by heating the mixture of anhydride and amine at a temperature of 65l50 C. for a period of time varying between one and three hours. The addition occurs readily without the formation of water. Less desirably, the amic acids can be prepared by the controlled reaction between succinic or maleic acid and the amine, with the elimination of one mole of water per mole of amic acid produced. Care must be exercised to avoid the elimination of two moles of water to form the cyclic imide. Regardless of the method used to form the amic acid, the salt thereof can be made readily by warming equimolar quantities of the amic acid with an aliphatic primary amine having between about 4 and about 30 carbon atoms per molecule. The salt-forming amine can be the same amine used in making the amic acid, or it can be a different amine. In the case where the salt-forming amine is the same used in the amic acid, the salt can be made by heating two moles of amine with one mole of acid anhydride under temperatures whereby water is not evolved.

The amines utilizable in forming the amic acids and the salts thereof are the primary aliphatic amines having between about 4 and about 30 carbon atoms per molecule. These are the monoamines having a single open chain hydrocarbon group attached to a nitrogen. The aliphatic radical can be saturated or unsaturated, and branched-chain or normal chain. Likewise mixtures of these amines, as well as pure amines, can be employed. A very useful and readily available class of primary amines are the tertiary alkyl, primary, monoamines in which a primary amino (-NH group is attached to a tertiary carbon atom; and mixtures thereof. These amines all contain the terminal group,

CH Non-limiting examples of the amine reactants are t-butyl primary amine, t-hexyl primary amine, n-hexylamine, noctylamine, n-octenylamine, t-octyl primary amine, 2- ethylhexylamine, t-decyl primary amine, n-decylamine, tdodecyl primary amine, n-undecylamine, dodecenylamine,

dodecadienylamine, tetradecylamine, t-tetradecyl primary amine, t-octadecyl primary amine, hexadecylamine, octadecenylamine, octadecadienyl amine, t-eicosyl primary amine, n-eiscosylamine, t-tetracosyl primary amine, pentacosylamine, and t-triacontyl primary amine. The amine reactants can be prepared in several ways well known to those skilled in the art. Specific methods of preparing the t-alkyl primary amines are disclosed in the Journal of Organic Chemistry, vol. 20, page 295 et seq. (1955). Mixtures of such amines can be made from a polyolefin fraction (e.g., polypropylene and polybutylene cuts) by first hydrating with sulfuric acid and water to the corresponding alcohol, converting the alcohol to alkyl chloride with dry hydrogen chloride, and finally condensing the chloride with ammonia, under pressure, to produce a t-alkyl primary amine mixture.

The fuel oils that are improved in accordance with this invention are hydrocarbon fractions having an initial boiling point of at least about 100 F. and an end boiling point no higher than about 750 F., and boiling substantially continuously throughout their distillation range. Such fuel oils are generally known as distillate fuel oils. It is to be understood, however, that this term is not restricted to straight-run distillate fractions. The distillate fuel oils can be straight-run distillate fuel oils, catalytically or thermally cracked (including hydrocracked) distillate fuel oils, or mixtures of straight-run distillate fuel oils, naphthas and the like, with cracked distillate stocks. Moreover, such fuel oils can be treated in accordance with well known commercial methods, such as, acid or caustic treatment, hydrogenation, solvent refining, clay treatment, etc.

The distillate fuel oils are characterized by their relatively low viscosities, pour points, and the like. The principal property which characterizes the contemplated hydrocarbons, however, is the distillation range. As mentioned hereinbefore, this range will lie between about 100 F. and about 750 F. Obviously, the distillation range of each individual fuel oil will cover a narrower boiling range falling, nevertheless, within the above-specified limits. Likewise, each fuel oil will boil substantially continuously throughout its distillation range.

Particularly contemplated among the fuel oils are Nos. 1, 2, and 3 fuel oils used in heating and as diesel fuel oils, and the jet combustion fuels. The domestic fuel oils generally conform to the specifications set forth in ASTM Specifications D396-48T. Specifications for diesel fuels are defined in ASTM Specifications D97548T. Typical jet fuels are defined in Military Specification MIL-F-5624B.

The amount of amic acid or amine salt of amic acid additives that is added to the distillate fuel oil in accordance withthis invention will depend, of course, upon the intended purpose and the particular amic acid or salt selected, as they are not all equivalent in their activity. Some may have to be used in greater concentrations than others to be effective. In most cases, in which it is desired to obtain all three beneficial results, namely, to inhibit sedimentation, to reduce screen clogging, and to prevent rusting of ferrous metal surfaces, additive concentrations varying between pounds per thousand barrels of oil and about 200 pounds per thousand barrels of oil will be employed. It may not always be desired, however, to accomplish all three aforementioned results. In such cases, where it is desired to effect only one or two results, lower concentrations can be used. Thus, if it is desired only to prevent rust under dynamic conditions, as in a pipeline, it has been found that concentrations as low as about 5 p.p.m., i.e., about one pound of additive per thousand barrels of oil, are effective. In general, therefore, the amount of amic acid or of amine salt of amic acid that can be added to the distillate fuel oil, in order to achieve a beneficial result, will vary generally between about one pound per thousand barrels of oil and about 200 pounds per thousand barrels of oil. Preferably, it will vary between about 10 and about 200 pounds per thousand barrels of oil.

If it is desired, the fuel oil compositions can contain other additives for the purpose of achieving other results. Thus, for example, there can be present foam inhibitors and ignition and burning quality improvers. Examples of such additives are silicones, dinitropropane, amyl nitrate, metal sulfonates, and the like.

The following specific examples are for the purpose of illustrating the fuel oil compositions of this invention, and of exemplifying the specific nature thereof. It is to be strictly understood, however, that this invention is not to be limited by the particular additives and fuel oils, or to the operations and manipulations described therein. Other amic acids or amine salts thereof and fuel oils, as discussed hereinbefore, can be used, as those skilled in the art will readily appreciate.

AMIC ACIDS AND SALTS The amine reactants used in the specific working examples are mixtures ofpure amines. Amine A is a mixture of primary amines having a carbon atom of a tertiary butyl group attached to the amino (--NH group and containing 12 to 15 carbon atoms per amine molecule and averaging 12 carbon atoms per molecule. This mixture contains, by weight, about 85 percent tertiary-dodecyl primary amine, about 10 percent tertiarypentadecyl primary amine, and relatively small amounts, i.e., less than about 5 percent of amines having less than 12 or more than 15 carbon atoms. Amine B is a mixture of tertiary-alkyl primary amines containing 18 to 24 carbon atoms per molecule and averaging about 20 carbon atoms per molecule. It has a tertiary carbon atom attached to the --NH group and contains, by weight, about 40 percent tertiary-octadecyl primary amine, about 30 percent tertiary-eiscosyl primary amine, about 15 percent tertiary-docosyl primary amine, about 10 percent tertiary-tetracosyl primary amine, and a small amount, less than 5 percent, other amines as high as tertiarytriacontyl primary amine.

Amine C, Amine D, and Amine E are mixtures of normal aliphatic primary amines having the weight percent compositions set forth in Table I.

Table I Normal Amine Amine O Amine D Amine E Tetradecyl- 2 Hexade cyl 10 24 OetadecyL 10 28 Example 1.A mixture of 100 grams (0.5 mole) of Amine A, 50 grams (0.5 mole) of succinic acid anhydride, and 50 grams of xylene, as diluent, was heated with agitation at -85 C. for 3 hours to form the succinamic acid. The reaction product was clear and fluid at room temperature.

Example 2.A mixture of 150 grams (0.5 mole) of Amine D, 50 grams (0.5 mole) of succinic acid anhydride, and l00 grams xylene diluent was heated at C. with agitation for 3 hours to form a succinamic acid.

Example 3.A mixture of 79 grams (0.615 mole) of Amine C, 61.5 grams (0.615 mole) succinic acid anhydride, and 140 grams of xylene diluent was heated at C. with stirring for 3 hours to form a succinamic acid.

Example 4.A mixture of grams (0.5 mole) of Amine A, 49 grams (0.5 mole) of maleic acid anhydride, and 75 grams of xylene diluent was heated at 65- 75 C. with agitation for 2 hours to form a maleamic acid.

Example 5.--A mixture of 95 grams /a mole) of Amine E, 33 grams /3 mole) of maleic acid anhydride,

and 128 grams of xylene diluent was heated at 75-85 C. with agitation for 3 hours to form a maleamic acid.

Example 6.-A mixture of 50 grams (0.25 mole) of Amine A, grams (0.25 mole) of succinic acid anhydride, and 67 grains of xylene diluent was stirred at 85 C. for 1.5 hours to form a succinarnic acid. To the succinamic acid, at room temperature, were added grams (0.25 mole) of Amine A to form the amine salt. The product was then stirred at 85-90 C. for an additional 1.5 hours.

Example 7.-A mixture of 67 grams (0.33 mole) of Amine A, 33 grams (0.33 mole) of succinic acid anhydride, and 100 grams of kerosine (B.R. 343-519 F.), as a diluent, was heated, with agitation, for 2 hours at 90 C. to form a succinamic acid. At room temperature, 100 grams (0.33 mole) of Amine D were added to form the amine salt. The material was then stirred at 90 C. for 2 more hours.

Example 8.-A mixture of 100 grams (0.5 mole) of Amine A, 50 grams (0.5 mole) of succinic acid anhydride, and 100 grams of xylene diluent was stirred at 75 C. for 2 hours to form a succinamic acid. At room temperature, 64.5 grams (0.5 mole) of Amine C were added to form the amine salt. The product was stirred at C. for 2 hours.

Example 9.A mixture of 50 grams (0.25 mole) of Amine A, 24.5 grams (0.25 mole) of maleic acid anhyd-ride, and 62 grams of xylene diluent was stirred at C. for one hour to form a maleamic acid. To the maleamic acid was added at room temperature 50 grams (0.25 mole) of Amine A to form the amine salt. The material was then stirred at 75 C. for 2 hours.

Example 10.A mixture of 49 grams (0.5 mole) of maleic acid anhydride and 118 grams (0.5 mole) of a technical grade of Amine A was stirred at 81 C. for 2 hours to form the maleainic a'oid. The product was viscous at room temperature. Thus, it was diluted with 167 grams of paraflinic oil (100 SSU at 100 F.). Example 11.A mixture of 303 grams (1.0 mole) of Amine B, 98 grams (1.0 mole) of maleic acid anhydride, and 200 grams of xylene diluent was stirred at C. for two hours to form the maleamic acid.

Example 12.-A mixture of 175 grams (0.57 mole) of Amine B, 57 grams (0.57 mole) of succinic acid anhydride, and 100 grams of xylene diluent was stirred at 90" C. for two hours to form the succinamic acid.

Example 13.-A mixture of 100 grams (0.5 mole) of Amine A and 50 grams (0.5 mole) of succinic acid anhy- ;dride was stirred at 90 C. for two hours to form the succinamic acid. To this acid, were added 151 grams (0.5 mole) of Amine B to form the amine salt. The material was stinred for 1.5 hours at C.

SEDIMENTATION The test used to determine the sedimentation characteristics of the fuel oils is the 110 F. storage test. In this test, a SOD-milliliter sample of the fuel oil under test is placed in a co-nyvected oven maintained at 110 F. for a period of 12 weeks. Then, the sample is removed from the oven and cooled. The cooled sample is filtered through a tared asbestos filter (Gooch crucible) to remove insoluble matter. The weight of such matter in -milligrarns is reported as the amount of sediment. A

sample of the blanlg uninhibited oil is run along with a fuel oil blend under test. The effectiveness of a fuel oil containing an inhibitor is determined by comparing the weight of sediment formed in the inhibited oil with that formed in the uninhibited oil.

Example 14.Additives described in Examples 1 6 of 60 percent distillate stock obtained from continuous catalytic cracking and 40 percent straight-run distillate stock. It has a boiling range of between about 320 F. and about 640 F. and is a typical No. 2 fuel oil.

' Table II 110 F. STORAGE TEST-12 WEEKS Inhibitor Example Inhibitor Sediment,

A01d Amie Salt Ooncn, mgjliter Anhydride Amine Amine lb./1000 bbls.

A i 50 D s a: A l 100 54 0 18 100 s 0 49 100 17 0 6 v 2g 2 Succinic...- B

1 Amine combined with anhydride to form the mic acid. 1 Amine used to form salt ofthe amic acid. a Hydrofined fuel oil.

SCREEN CLOGGING The anti-screen clogging characteristics of a fuel oil were determined as follows: The test is conducted using a Sundstrand V3 or S1 home fuel oil burner pump with a self-contained 100'-mesh Monel metal screen. About 0.05 percent, by weight, of naturally-formed fuel oil sediment, composed of fuel oil, water, dirt, rust, and organic sludge is mixed with 10 liters of the fuel oil. This mixture is circulated by the pump through the screen for 6 hours. Then, the sludge deposit on the screen is washed off 'With normal pentane and filtered through a tared Gooch crucible. After drying, the material in Gooch crucible is washed with a 50 -50 (volume) acetone-methanol mixture. The total organic sediment is obtained by evaporating the pentane and the acetone-methanol filtrates. Drying and Weighing the Gooch crucible yields the amount .of inorganic sediment. The sum of the organic and inorganic deposits on the screen can be reported in milligrams recovered or converted into percent screen clogging.

Example 15.Using the test fuel oil described in Example 14, blends of additives of Examples 1 through 13 in this fuel were prepared. Each blend was subjected.

to the screen clogging test, as aforedescribed. Test results are set forth in Table HI.

Table III SCREEN CLOGGING Concn, Screen Additive of Example lbs/1,000 Clogging,

. bbls. Percent Blank 0 100 1 100 8 2 100 5 4 100 83 E 100 6 6 50 21 7 100 0 8 100 2 9 100 43 10. 100 44 11 25 3 12. 25 12 13- 25 5 RUSTING Two methods were used for testing anti-rust properties 7 of the fuel oils. One test was the ASTM Rust Test D-665 operated for 48 hours at 80 F. using distilled water. This is a dynamic test that indicates the ability to prevent rusting of ferrous metal surfaces in pipelines, tubes, etc.

The other test is a static rust test which simulates conditions encountered in storage tanks, such as, the home fuel oil storage tank. In this test, a strip of 16-20 gauge sand blasted steel plate is placed in a clear quart bottle. The length of the strip is suificient to reach from the bottom of the bottle into the neck of the bottle without interfering with the cap. One hundred cc. of synthetic sea water with pH adjusted to (ASTM D-6 65) and 750 cc. of test oil are placed in the bottle. The bottle is capped tightly, shaken vigorously for one minute, and permitted to stand quietly at 80- F. for 21 days. At the end of that time, the amount of rust that occurs on the surface of the plate immersed in the water is used as a measure of effectiveness of the fuel to inhibit rusting in storage vessels. It is generally preferred that no more than 5 percent of the surface should be rusted. This test is much more severe than the ASTM rust test. Many additive compositions that pass the ASTM test fail in the static test. On the other hand materials that pass the static test always pass the ASTM test.

Example 16.Blends of additives described in EX- amples 1 through 13 in the fuel oil of Example 14 were subjected to the ASTM Rust Test D-665. Pertinent data are set forth in Table IV.

Table IV ASTM RUST TEST Additive of Example Concn, Test ppm. Result Blank O Fail. 1 5 Pass. 2 Do. 3. 25 Do. 4.. 100 D0. 5 25 Do. 6 10 Do. 7 5- D0. 8 10 Do. 9 100 D0. 11 12- 13- 10 D0.

Example 17.-The' additives described in Examples 1, 2, 3, 5, 6, 7, 8, and 13' were each blended with portions of the fuel oil of Example 14. The blends were subjected to the static rust test. Pertinent data are set forth in Table V.

It will be apparent, from the data set forth in Tables II through V, that the maleamic acid and succinamic acids of this invention and amine salts thereof are highly effective to reduce sedimentation. and screen clogging and to inhibit rusting of ferrous metal surfaces under static and dynamic conditions. As is tobe expected results will vary among specific materials used. In order to accomplish any given improvement, many of the additives can be used in relatively small amounts, as for dynamic rust prevention. If, on the other hand, it is desired to accomplish all the aforementioned beneficial results, this can be accomplished at the practical additive concentration of 50-100 pounds per thousand barrels of fuel oil.

Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations may be resorted to, without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such variations and modifications are considered to be within the purview and scope of the appended claims.

What is claimed is:

1. A distillate fuel oil containing a small amount, sufiicient to inhibit sedimentation and screen clogging and to prevent rusting of ferrous metal surfaces in contact therewith, of a compound selected from the group consisting of (l) a succinamic acid having the'formula:

OH2-CH2 0 COOH RHN 0 wherein R is a monovalent aliphatic hydrocarbon radical having between about 4 and about 30 carbon atoms; (2) a maleamic acid having the formula:

oH=oH ll. oooon RHN 0 wherein R is a monovalent aliphatic hydrocarbon radical having between about 4 and about 30 carbon atoms; and (3) the salts of (1) and (2) with unsubstituted aliphatic primary amines having between about 4 and about 30 carbon atoms per molecule.

2. A distillate fuel oil containing between about one pound and about 200 pounds per thousand barrels of fuel of a compound selected from the group consisting of (1) a succinamic acid having the formula:

GHQ-CH1 UOOH RHN 0 wherein R is a monovalent aliphatic hydrocarbon radical having between about 4 and about 30 carbon atoms; (2) a maleamic acid having the formula:

H=C|lH 0 COOH RHN 0 wherein R is a monovalent aliphatic hydrocarbon radical having between about 4 and about 30 carbon atoms; and (3) the salts of (1) and (2) with unsubstituted aliphatic primary amines having between about 4 and about 30 carbon atoms per molecule.

3. A distillate fuel oil containing between about 10 pounds and about 200 pounds per thousand barrels of fuel of a succinamic acid having the formula,

wherein R is a monovalent alkyl radical containing between about 12 and about 15 carbon atoms and having a tertiary carbon atom directly attached to the nitrogen atom.

4. A distillate fuel oil containing between about 10 pounds and about 200 pounds per thousand barrels of fuel of a succinamic acid having the formula,

wherein R is a mixture of 10 percent hexadecyl, 10 percent octadecyl, 35 percent octadecenyl, and 45 percent octadecadienyl radicals.

5. A distillate fuel oil containing between about 10 pounds and about 200 pounds per thousand barrels of fuel of an amine salt of a succinamic acid having the formula,

wherein R is a monovalent alkyl radical containing between about 12 and about 15 carbon atoms and having a tertiary carbon atom directly attached to the nitrogen atom, with a primary monoalkyl amine wherein the alkyl group contains between about 12 and about 15 carbon atoms and having a tertiary carbon atom directly attached to the -NH group.

6. A distillate fuel oil containing between about pounds and about 200 pounds per thousand barrels of fuel of an amine salt of a succinamic acid having the formula,

wherein R is a monovalent alkyl radical containing between about 12 and about 15 carbon atoms and having a tertiary carbon atom directly attached to the nitrogen atom, with a mixture of primary amines containing 10 percent hexadecyl, 10 percent octadecyl, percent octadecenyl, and percent octadecadienyl amines.

References Cited in the file of this patent UNITED STATES PATENTS 2,191,738 Balle Feb. 27, 1940 2,279,560 Dietrich Apr. 14, 1942 2,588,412 Rocchini Mar. 11, 1952 2,604,449 Bryant et al July 22, 1952 2,604,451 Rocchini July 22, 1952 2,647,872 Peterson Aug. 4, 1953 2,699,427 Smith et al Jan. 11, 1955 2,718,503 Rocchini Sept. 20, 1955 2,783,206 Messina Feb. 26, 1957 2,908,711 Halter et al Oct. 13, 1959 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Noe 3,03%282 April 24, I962 Harry I, Andreas Jr, et all It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, lines 4 to "I, the formula should appear as shown below instead of as in the patent:

.TH IH C OOH column 8 lines 12, 33 53 64 75. and column 9 line 15, for "A distillate fuel oil" each occurrence read A petroleum distillate fuel oil having an initial boiling point of at least about 100 F, and an end boiling point no higher than about 75C) Fe n Signed and sealed this 20th day of November 19620 (SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents 

1. A DISTILLATE FUEL OIL CONTAINING A SMALL AMOUNT, SUFFICIENT TO INHIBIT SEDIMENTATION AND SCREEN CLOGGING AND TO PREVENT RUSTING OF FERROUS METAL SURFACES IN CONTACT THEREWITH, OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF (1) A SUCCINAMIC ACID HAVING THE FORMULA: 